Clamping device

ABSTRACT

A cam operated clamping device for holding sheet material along one edge. The clamp has a support member and a pair of angular gripping arms pivotally connected to the support member. The movement of the gripping arms to open and close the clamp is facilitated by a cam mechanism controlled from one end of the clamp. Each of the angular gripping arms has two sections wherein the first section holds the sheets and the second section reacts to the movement of the cam mechanism, causing the opening and closing movement of the first section. An additional embodiment of the device allows interchangeability with regard to attachment to a support hanger.

United States Patent Petrie 1 June 24, 1975 541 CLAMPING DEVICE 3.308.831 3/1967 Kritske 24/67.] 3,729.099 4/1973 Kritske 211/46 Gordon D. Petrie, 11428 Snowdrop Ave.. Fountain Valley. Calif. 92708 [76] Inventor:

Primary Examiner-Ramon S. Britts Attorney. Agent. or Firm-Knobbe. Martens. Olson. Hubbard & Bear [57} ABSTRACT A cam operated clamping device for holding sheet material along one edge. The clamp has a support member and a pair of angular gripping arms pivotally connected to the support member. The movement of the gripping arms to open and close the clamp is facilitated by a cam mechanism controlled from one end of the clamp. Each of the angular gripping arms has two sections wherein the first section holds the sheets and the second section reacts to the movement of the cam mechanism, causing the opening and closing movement of the first section. An additional embodiment of the device allows interchangeability with regard to attachment to a support hanger.

16 Claims, 7 Drawing Figures PATENTEDJUM 24 ms 3 8 91. 093

SHEET 1 Jr/{ Z ja 1 CLAMPING DEVICE BACKGROUND OF THE INVENTION This invention relates to the field of clamp binders for holding sheet material such as maps. blueprints, engineering drawings. etc. These types of binders are used to provide not only convenient storage. but also convenient access for easy review of the sheets. This type of arrangement of large sheets has proved to be very desirable and advantageous as opposed to the more cumbersome and annoying process of folding the sheets.

The art of providing a binder for the hanging and storage of such sheets is well established; however, cer tain disadvantages remain which require solution. In one common type of clamp hinder the control for the operation of the clamp mechanism consists of a plurality of manually operated nut and bolt combinations. Consequently, each time an individual wishes to remove one or more of the large sheets from the binder, he must manually loosen each nut or bolt in order to release the clamp pressure. This type of operation is very time consuming and. therefore. a source of wasted time to the professional and high salary personnel, utilizing these blueprints. engineering drawings, etc.

A few prior art binders reflect the concept ofa clamp mechanism. having its control mechanism at a single point. However, the configuration of these devices if awkward and does not provide the ease of one hand operation. because the usual turning mechanism to operate the clamp requires a significant amount of force. This is due to the fact that prior art devices utilize a shifting pivot axis for the gripping clamp for movement into a fixed channel. requiring significant force because of the effect of the weight and bulk of the group of sheets in moving the pivot axis. To help alleviate the need for the application of considerable force to operate the clamp some devices have incorporated the use of a cam mechanism; however, the necessary force to operate the clamp remains too high to provide convenient and easily operable single point control.

Commonly, a group of clamping devices of this type are suspended by suitable brackets to provide adequate support for heavy sheet material. However, in actual practice the sheet material frequently is small and relatively light. and the typical binder is too large for various lighter sheet materials and occupies too great a space. A need exists for the ability to interchange binders on the same support brackets to handle both heavy and light sheet material.

SUMMARY OF THE INVENTION The invention disclosed herein provides a binder to hold and support numerous sheets of varying sizes. The device includes an elongated channel member with a pair of clamping jaws which pivot on fixed axes at tached to the channel member. The clamping jaws are angled; and the attachment of each clamping jaw to the channel member is at the vertex of the angle, forming a pair of gripping legs and a pair of bearing legs. A cam mechanism is used to open and close the gripping legs and is operated from a single point on the channel member. This single point of operation greatly reduces the time required to remove and replace sheets.

The pivoting of the clamping jaws around a fixed axis rather than a shifting axis promotes the ease in the effect necessary to operate the gripping legs, because there is no lost effort in having to vertically raise the heavy weight or bulk of the sheets in order to facilitate the closing of the gripping legs. The clamping jaws are simply rotated to the closed position and. therefore. the amount of force necessary to bind the sheets is minimal.

An embodiment of the invention allows the inter changeability of support members for connection with the attachment members of a support bracket. If there are particular sets of lighter sheet material covering different subject matter it would be advantageous to maintain them in separate binders. The device presented herein allows the use of two separate support members to be suspended from one support bracket by utilization of each of the two attachment members on support brackets.

The present invention also incorporates an embodiment which has the advantage of being a single piece, formed by the extrusion of a plastic-like material.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view ofa preferred form of the clamp in its normal hanging position;

FIG. 2 is a sectional view of the clamp of FIG. I;

FIG. 3 is a sectional view of a second embodiment of the invention",

FIG. 4 is a sectional view taken along the lines 4-4 in FIG. 2, showing the cam mechanism for moving the clamping jaws;

FIG. 5 is a sectional view taken along the lines 5-5 in FIG. 3, showing the cam mechanism for moving the clamping jaws with the lever handle in the close clamp position;

FIG. 6 is a sectional view taken along the lines 5-5 of the phantom position in FIG. 3 with the lever handle in open clamp position;

FIG. 7 is a perspective view of a lever mechanism for operating the cam mechanism in the clamping device of FIGS. 1 and 2.

DETAILED DESCRIPTION OF INVENTION Referring first to FIGS. 2 and 4, there is shown an elongated, downwardly opening channel-like support member 10 having a lower section 12 and an upper section 14. The lower section 12 comprises a pair of lower walls 16 and 18 extending downward and slightly angled outward away from each other. In the approximate middle of the inside surface 20 of each lower wall is a guide flange 22, extending inward toward each other. Located between the guide flanges 22 is a slot 24. Formed on the bottom edge 26 of each lower side of the support member 10 is a pivot bar 28 and connected to each pivot bar 28 respectively is a first jaw or holding member 30 and a second jaw or holding member 32. Each holding member or clamp member 30 and 32 has an interior flange or pivot leg 34 and a gripping leg 36. The pivot or bearing leg 34 and gripping leg 36 meet at an angle, forming a rigid junction 38, which comprises a longitudinal cylindrical section. having a semicircular cross section as shown in FIG. 2 with an inner surface 40 designed to receive the pivot bar 28. The lower end 42 of each gripping leg 36 terminates in a gripping edge 44.

Situated below and contacting the lower surface 46 of the pivot legs 34 is a cam rod 48, which has a curved upper surface 50 and a flat lower surface 52. As shown in FIG. 4, attached edgewise to the upper surface 50 of the cam rod 48 are two cam blades 54 of trapezoidal shape, having parallel inclined front 56 and rear 58 edges. Slideably engaging the cam blades 54 is an actuator element or slide element 60 having two cam slots 62. The actuator element 60 is an elongated fiat member which is slideably supported within the support member by the guide flanges 22. Each cam slot 62 respectively receives a cam blade 54. The width 64 of the cam slots shown in FIG. 7 is slightly larger than the lateral width 66 of each cam blade 54 while the length 68 of the cam slots as shown in FIG. 4 is larger than the longitudinal length 70 of each cam blade 54. Since the cam rod 48 is freely suspended on the actuator element 60 by the cam blades 54, the restraining member 71 is attached behind the front end 73 of the support member 10 in order to restrain the front end of the cam rod 48 from moving forward which would result in the cam rod 48 slipping downward.

Attached to the front end 72 of the actuator element 60 is a control mechanism, shown generally at 74 in FIG. 4, which has a bracket 76, extending forward from the actuator element 60. At the extreme forward end of the bracket is a holding flange 78 having a threaded hole 80. Threadably received into the hole 80 is a threaded shaft 84, having one end 86 extending through the front end 73 of the support member 10 and connected to a control knob 88.

With respect to FIG. 2, mounted around the upper surface 50 of the cam rod 48 are two leaf springs 90 having two downward extending leaves 92 and 94. One leaf 92 is biased against the inside surface 96 of the gripping leg 36 of the first holding member 30 and the second leaf 94 is biased against the inside surface 98 of the gripping leg 36 of the second holding member 32.

Referring to FIG. 2, an elongated mounted bracket or support hangar 136 is shown, having an inverted U- shape forming two inverted T shaped attachment members 134a and 134b. Each attachment member has a pair of horizontal flanges 144 and 146, extending outwardly from opposite sides of the lower end of a vertical portion 138. The upper portion 14 of the support member 10 has a pair of side channels or elongated grooves 130 and 132, which open outwardly on opposite sides of the member 10. The respective side channels are designed to slideably receive the attachment members 1340 and 1341).

A second embodiment of the control mechanism is shown in FIG. 7 generally at 100 and has a lever arm 102 having one end 104 connected to the support member 10. A linkage member 106 is pivotally attached at its first end 108 to the lever arm 102 at a point approximately at the middle of the lever arm 102, but slightly toward the one end 104 connected to the support member 10. The second end 110 of the linkage member 106 is pivotally attached to a slide ram 112 comprising a circular ring 112 mounted on a slide bar 114 which is connected within the forward end 72 of the actuator or slide element 60. The forward end 72 of the actuator element 60 has an elongated slot 116 having first and second end surfaces 118 and 120. Connected between these end surfaces is the slide bar 114. The slide ram 112 is loosely mounted on the slide bar 114 to allow sliding of the slide ram 112. Located on the slide bar adjacent the first end 118 surface of the elongated slot 116 is a compression nut 122 threadably mounted on the slide bar and situated around the slide bar 114 between the slide ram 112 and the compression nut 122 is a compression spring 124. The slide bar 112 extends through the first end surface 118 of the elongated slot 116 and out the front edge 126 of the actuator element 60 forming a compression spring adjustment knob 128.

A second embodiment of the invention is reflected in FIGS. 3, 5 and 6. A support member 148 has a lower portion 150 and an upper portion 152. The lower portion 150 is comprised of a pair of lower walls 154 forming an open channel 156. Approximately midway down the lower walls 154 extending inwardly from the inside surface 158 of the lower walls are a pair of support flanges 160 defining a slot 162 between them. Attached to the bottom edge 164 of the lower walls of the lower portion 150 are a pair of holding members--21 first holding member 166 and a second holding member 168. Each holding member or jaw 166 and 168 has a pivot leg or interior flange 170 as well as a gripping leg 172. The pivot leg 170 and gripping leg 172 of each holding member 166 and 168 intersect, forming a rigidjunction 174, which is integrally connected to the bottom edge 164 of each lower wall 154, forming a living hinge 175. lntegrally attached by a living hinge 178 to each pivot leg or actuating end 170 of each holding member or gripping arm 166 and 168 is a hinge member 176. The hinge member of each actuating end 170 is integrally attached by a living hinge 179 to the bottom 178 of a push rod 180, which extends up through the slot 162 formed by the pair of support flanges 160. The push rod 180 has a top flange 182. At the lower extremity 184 of each gripping leg 172 is an inward extending gripping edge 186.

As shown more clearly in FIGS. 5 and 6, located between the upper surface 188 of the support flanges 160 of the lower walls and the lower surface 190 of the top flange 182 of the push rod 180 are a pair of elongated top spring members or actuator elements 192:: and 192b and a pair of elongated bottom spring members or cam members 194a and 19411. The pair of top spring members have a series of hills 195 and valleys 196, and the pair of bottom spring members have a series of hills 197 and valleys 108. The series of hills and valleys of each pair of spring members are sinusoidally identical. Connected to the respective front ends 200 and 202 of each pair ofthe elongated spring members 192 and 194 is a connecting pin 199 and 201 which attach each of the spring members to a lever mechanism 204, which has a lever handle 206 with one end 208 extending out of the front 210 of the support member 148 through an operating slot having an upper end 213 and a lower end 215. The other end 212 of the lever handle 206 is attached to the middle of a linkage member 214. The linkage member 214 is pivotally attached to the support member 148 by a pivot pin 216 extending through the middle of the linkage member. The linkage member 214 has atop end 218 and a bottom end 220 with each end having a slide slot 222 and 224 respectively. Slideably positioned within the slide slot 222 of the top end 218 is the connecting pin 199 of the elongated pair of top spring members or slide elements 192 and slideably positioned within the slide slot 224 of the bottom end 220 is the connecting pin 201 of the pair of elongated bottom spring members or cam members 194.

Referring to FIG. 3, located in the upper portion 152 of the support member 148 are two upper walls 226 and 228 forming an open attachment channel or elongated slot 230. At the top end of each upper wall 226 and 228 is a respective inward hanging flange 232 and 234. Mounted within the attachment channel is an attachment member I34. as discussed previously.

OPERATION Referring to the operation of the embodiment shown in FIGS. 2 and 4 with the first controlling mechanism. a person may readily operate the opening and closing of the gripping legs 36 and edges 44 by the rotation of the control knob 88. By rotating the knob 88 in the clockwise direction the actuator element 60 is brought forward in the direction of arrow fand as a result of this movement the cam blades 54 will ride up on their inclined front 56 and rear 58 surfaces into the cam slots 62. This will cause the cam rod 48 to raise vertically to the lock position as shown in the solid lines of FIG. 2, forcing the pivot legs 34 to pivot upward. Consequently. the gripping legs 36 and gripping edges 44 will pivot toward each other compressing the leaf springs 90 and will clamp onto the sheets 236 to be held.

Rotation of the control knob 88 in the counterclockwise direction will move the actuator element 60 to the rear. allowing the cam blades 54 to ride down their inclined surfaces 56 and 58. The cam rod 48 will drop vertically to the position shown in dashed lines in FIG. 2, allowing the pivot legs 34 to pivot downward, resulting in the leaf springs 90 forcing open the gripping legs 36. The opening of the gripping legs 36 facilitates the removal of all or any number of the sheets 236.

Using the second control mechanism I00 shown in FIG. 7. the operation of the gripping legs 36 is by the manipulation of a lever arm I02. When the lever arm I02 is rotated to the lower position. in the direction of the arrow, the slide ram 112 moves forward on the slide bar II4 compressing the compression spring I24 against the compression nut 122 to the point where the actuator element 60 moves forward, causing the cam blades 54 to ride up their inclined surfaces etc.. as discussed previously. When the lever arm is in the lower position. the force of the spring I24 on the linkage member I06 keeps the gripping legs 36 in the locked position as shown in the solid lines of FIG. 2. Movement of the lever arm I02 to the upper position slides the actuator element 60 to the rear allowing the gripping legs 36 to separate, releasing the sheets 236 as shown in the dashed lines of FIG. 2.

The upper section I4 of the support member 10 is connected to the mounting bracket 136 by utilizing two adjacent attachment members 1340 and I341) slideably attached to the support member 10. The second flange I46 of one attachment member 1340 is received in the first side channel I of the support member 10 and the first flange I44 of the adjacent attachment member 13411 is received in the second side channel I32 of the support member I0. Removal of the support member 10 from the attachment members 134a and 13419 is possible by sliding the support member I0 forwardly endwise the entire length of the attachment members 1340 and 134i) This removal may be convenient in order to leaf through the sheets 236 while they are still bound together. molding disarrangement. To reattach the support member I0. the side channels I30 and I32 are aligned with the flanges 146 and 144 of the respective attachment members 1340 and I34h.

With respect to the operation of the second embodiment of the invention reference is made to FIGS. 3, 5 and 6. The le\cr handle 206 controls the opening and closing of the gripping legs or ends 172. With the lever handle 206 in the horizontal position as shown in FIG. 5 the valleys 196 of the pair of elongated top spring members 192 are contacting the hills I97 of the pair of bottom elongated spring members 194. This offset orientation of the spring members results in the hills 195 of the top spring members I92 to bias against the lower surface of the top flange 182 of the push rod 180, forcing the push rod in the upper position shown in FIG. 3. To lock the spring members in this offset orientation the valleys I96 of the top spring members I92 are slightly forward of the hills 197 of the bottom spring members 194 in the forward direction of the arrow f. Therefore, the bills 197 of the bottom spring members 194 will prevent the rear movement of the top spring members 192. Since the lower end 215 of the operating slot in the front end 210 of the support member 148 prevents any further downward motion of the lever handle 206, the top spring members I92 cannot move forward.

When the push rod 180 is moved to the upper position of FIG. 3, the hinge members 176 are raised by the living hinges 179, causing the pivot legs I to come up by the connection to the living hinges 177. As a result, the gripping legs 172 are rotated around the living hinges 175 to the closed position for holding sheets. In order to open the gripping legs 172 the push rod must be lowered to the position shown in the dashed lines of FIG. 3. This is accomplished by rotating the lever handle 206 to the up position as shown in FIG. 6. This movement of the lever handle 206 will not only cause the top spring members I92 to move toward the rear, but also cause the bottom spring members I94 to move toward the front, resulting in the mating of the valleys 196 of the top spring members with the valleys 198 of the bottom spring members.

As reflected in FIG. 3, the upper section 152 of the support member 148 has an attachment member 134a, having the same configuration as that discussed above in conjunction with the preferred embodiment of the invention and shown in FIG. 2. The attachment channel 230 of the support member I48 slideably receives the attachment member I34a. The inward hanging flanges 232 and 234 in the upper section 152 of the support member I48 extend over the first and second flanges 144 and I46 of the attachment member 1340. Therefore, two support members 148 of the second embodiment of the invention may be connected to the mounting bracket 136 instead of only one of support members 10 of the clamping device shown in FIG. 2. This is accomplished by placement of the second support member in connection with the adjacent attachment member l34b.

The support member 10 of the first embodiment of the clamping device as shown in FIGS. I or 2 is designed to be manufactured from extruded aluminum or other lightweight material. The remaining elements of this first embodiment are separately made also from various lightweight materials such as aluminum or plastic-like compounds.

The second embodiment of the clamping device is designed to be extruded except for the separate elongated spring members I92 and 194 in a single piece from any of a number of various plastic-like compounds. This single piece construction results in the formation of the various living hinges 175, I77 and ing pro- 17 t allows more simplilied it. .uiac

cesses.

What is cla; net. is:

l. A clamping device foi holding sheet material comprising:

a support member having an upper portion and a lower portion;

a pair of clamp jaws pivotally attached to said lower portion of said support member and having a pair of interior flanges;

an actuator element slideably mounted within said support member and having a cam slot;

means located between said actuator element and said pair of clamp jaws for pivoting said pair of clamp jaws in response to the slideable movement of said actuator element. said means for pivoting said pair of clamp jaws comprises a cam rod mounted below said interior flanges of said pair of clamp jaws and a cam blade attached to said cam rod, said cam blade having an inclined cam surface and slideably extending into said cam slot; and

means attached to said actuator element for controlling said slideable movement of said actuator element.

2. A clamping device for holding sheet material comprising:

a support member having an upper portion and a lower portion;

a pair of clamp jaws pivotally attached to said lower portion of said support member and having a pair of interior flanges;

an actuator element slideably mounted within said support member;

means located between said actuator element and said pair of clamp jaws for pivoting said pair of clamp jaws in response to the slideable movement of said actuator element, said means for pivoting said pair of clamp jaws comprises a push rod, hav ing its lower end in contact with said actuator element, a cam member attached to said support member and located between said lower end and said upper end of said push rod, and a cam surface on said actuator element in slideable contact with said cam member for moving said push rod to pivot said pair of clamp jaws; and

means attached to said actuator element for controlling said slideable movement of said actuator element.

3. A clamping device for holding sheet material comprising:

a support member having an upper portion and a lower portion;

a pair of clamp jaws pivotally attached to said lower portion of said support member;

an actuator element slideably mounted within said support member;

means located between said actuator element and said pair of clamp jaws for pivoting said pair of clamp jaws in response to the slideable movement of said actuator element; and

means attached to said actuator element for controlling said slideable movement of said actuator element, said controlling means comprising a control knob rotatably mounted on the end of said support member, a threaded shaft extending from said knob through said support member, and a connecting bracket thread-ably mounted on said shaft and actuator element will move r i s. -lLll. i tell knob is rotated, sa d longitudinally,

4. A clamping device for holding sheet material comprising an elongated support member ha ing an upper portion and a lower portion;

a pair of clamp jaws pivotally mounted to said lower portion of said support member;

an actuator element slideably mounted along the longitudinal axis of said support member;

cam means is responsive contact with said actuator element for pivotally moving said pair of clamp jaws;

a lever, having one end pivotally attached to said support member;

a linkage member having one end pivotally attached to said lever and the other end pivotally attached to said actuator element; and

means located between said linkage member and said actuator element for slideably moving said actuator element in response to the movement of said lever.

S. A clamping device for holding sheet material comprising;

a support member having an upper portion and a lower portion;

a pair of clamp jaws pivotally attached to said lower portion of said support member;

an actuator element slideably mounted within said support member;

means located between said actuator element and said pair of clamp jaws for pivoting said pair of clamp jaws in response to the slideable movement of said actuator element; and

means attached to said actuator element for controlling said slideable movement of said actuator element, said controlling means comprises a lever having one end pivotally attached to said support member a linkage member having one end pivotally attached to said lever and the other end pivotally attached to said actuator element, and means located between said linkage member and said actuator element for slideably moving said actuator element in response to the movement of said lever, said means for slideably moving said actuator element comprises a slide shaft attached to said actuator element, a slide ram mounted on said slide shaft, an adjustable restraining ring mounted on said slide shaft, and a spring mounted on said slide shaft between said slide ram and said adjustable ring, so that as said lever is rotated in a downward direction, said linkage member will cause said slide ram to compress said spring against said restraining ring, causing said actuator element to move longitudinally.

6. A clamping device comprising:

a support member;

a first holding member, having a pivot leg and a gripping leg. the lower end of said pivot leg being connected at an angle to the upper end of said gripping leg, forming a rigid junction;

a second holding member, having a pivot leg and a gripping leg, the lower end of said pivot leg being connected at an angle to the upper end of said gripping leg, forming a rigid junction, said rigid junction of said first holding member and said rigid junction of said second holding member being pivotally attached to said support member; and

9 means located in said support member for urging the movement of said pivot legs of said holding members. so that the lower ends of said gripping legs will move toward each other. said means for urging the movement of said pivot legs of said holding members comprises a slide element slideably mounted for longitudinal movement within said support member, above said holding members. said slide element having a cam slot. a cam rod located under said pivot legs of said holding members. said cam rod havinga cam blade with an inclined cam surface extending into said cam slot. so that said longitudinal movement of said slide element causes vertical movement of said cam rod to pivot said holding members, and means for controlling said longitudinal movement of said slide element. 7. A clamping device as defined in claim 6, wherein said means for controlling said longitudinal movement of said slide element comprises:

a control knob rotatably mounted on said support member;

a threaded shaft extending from said knob through said support member; and

a connecting bracket threadably mounted on said shaft and attached to said slide element. so that as said knob is rotated, said slide element will move longitudinally.

8. A clamping device as defined in claim 6, wherein said means for controlling said longitudinally movement of said slide element comprises:

a lever, having one end pivotally attached to said support member; r

a linkage member having one end pivotally attached to said lever and the other end pivotally attached to said slide element; and

means located between said linkage member and said slide element for slideably moving said slide element in response to the movement of said levert 9. A clamping device comprising:

a support member;

a first holding member. having a pivot leg and a gripping leg. the lower end of said pivot leg being connected at an angle to the upper end of said gripping leg, forming a rigid junction;

a second holding member, having a pivot leg and a gripping leg. the lower end of said pivot leg being connected at an angle to the upper end of said gripping leg, forming a rigid junction. said rigid junction of said first holding member and said rigid junction of said second holding member being pivotally attached to said support member; and

means located in said support member for urging the movement of said pivot legs of said holding members. so that the lower ends of said gripping legs will move toward each other. said means for urging the movement of said pivot leg of said holding members comprises, a push rod. having a lower end and an upper end. said lower end being attached to said pivot legs of said first and second holding members. such that vertical movement of said push rod pivots said holding members. a cam member attached to said support member and located between said lower end and said upper end of said push rod. a slide element slideably mounted within said support member. a cam surface on said slide element. said cam surface being in slideable contact with said cam member. so that the longitu- 10 dinal movement of saidslid'e element will cause the vertical movement of said push rod. and means for controlling said longitudinal movement of said slide element. 10. A clamp device comprising: i

a channel member, having an upper section and a lower section;

an actuator element slideably mounted longitudinally within said channel member and having a cam slot;

means attached to said actuator element for controlling the movement of said actuator element;

a pair of clamp members. having a bearing leg and a gripping leg and being pivotally attached to said channel member at the rigid angular junction of said bearing leg and said gripping leg;

a cam rod located between said bearing legs of said pair of clamp members. said cam rod being wider than the distance between the upper ends of said bearing legs;

means for biasing said gripping legs in the open position; and

a cam blade attached to the upper side of said cam rod and extending slideably into said cam slot of said actuator element. said cam blade having an inclined cam surface, so that, as said actuator element is longitudinally moved, said cam rod will move vertically, causing said bearing legs to move down or up. resulting in said gripping legs opening or closing.

11. A clamp device as defined in claim 10, wherein said means for controlling the movement of said actuator element comprises:

a control knob rotatably mounted on said channel member;

a threaded shaft extending from said knob and through said channel member, and

a connecting bracket threadably mounted on said shaft and attached to said actuator element, so

that. as said knob is rotated. said actuator element will move longitudinally.

12. A clamp device as defined in claim 10, wherein said means for controlling the movement of said actuator element comprises:

a lever. having one end pivotally attached to said channel member;

a linkage member, having one end pivotally attached to said lever and the other end pivotally attached to said actuator element; and

means located between said linkage member and said actuator element for slideably moving said actuator element in response to the movement of said lever.

13. A clamp device as defined in claim 10, wherein said means for biasing said gripping legs in the open position comprises a spring biased against the interior sides of said gripping legs of said pair of clamp members.

14. A clamping device comprising:

a channel member;

a first leg extending downward from said channel member;

a second leg extending downward from said channel member, forming an open channel with said first ts;

a pair of support flanges respectively attached to the interior surfaces of said first and second legs, said support flanges in alignment with each other. forming a longitudinal slot;

a pair of gripping jaws pivotally attached to respective lower ends of said first and second legs; and

camming means located on the upper surface of said support flanges, movement of said gripping jaws responsive to said camming means.

15. A clamping device comprising:

a channel member;

a first leg extending downward from said channel member;

a second leg extending downward from said channel member, forming an open channel with said first leg;

a pair of support flanges respectively attached to the interior surfaces of said first and second legs. said support flanges in alignment with each other, forming a longitudinal slot;

a pair of gripping jaws pivotally attached to respective lower ends of said first and second legs; and means located on the upper surface of said support flanges and attached to said gripping jaws for pivoting said gripping jaws, said means for pivoting said gripping jaws comprises:

a push rod, having a top flange, said push rod connected to said gripping jaws;

an elongated bottom spring member located on said upper surface of said support flanges and below said top flange of said push rod, said bottom spring member having a series of hills and valleys;

an elongated top spring member located between said bottom spring member and said top flange of said push rod, said top spring member having a series of hills and valleys, so that, as said top spring member is longitudinally slid over said bottom spring member, said push rod will be in the upper position when said valleys of said top spring member contact said hills of said bottom spring members and said push rod will be in the lower position when said valleys of said top spring member contact said valleys of said bottom spring member; and

means for controlling said longitudinal movement of said elongated top spring member.

16. A clamp apparatus comprising:

a support member, having an upper portion and a lower portion;

a pair of pivoting gripping arms attached to said lower portion of said support member, said gripping arms having a gripping end and an actuating end;

a push rod mounted within said support member and attached to said actuating ends of said pair of gripping arms; and

means located within said support member for vertically moving said push rod, causing said pivoting movement of said gripping arms, said means for vertically moving said push rod comprises:

a cam mounted within said support member;

an actuator element slideably mounted longitudinally within said support member between said push rod and said pair of gripping arms, said actuator element having a cam surface, so that as said actuator element is longitudinally moved, the contact of said cam of said support member and said cam surface of said actuator element will cause said push rod to move vertically; and

means attached to the end of said actuator element for controlling said longitudinal movement of said actuator element. 

1. A clamping device for holding sheet material comprising: a support member having an upper portion and a lower portion; a pair of clamp jaws pivotally attached to said lower portion of said support member and having a pair of interior flanges; an actuator element slideably mounted within said support member and having a cam slot; means located between said actuator element and said pair of clamp jaws for pivoting said pair of clamp jaws in response to the slideable movement of said actuator element, said means for pivoting said pair of clamp jaws comprises a cam rod mounted below said interior flanges of said pair of clamp jaws and a cam blade attached to said cam rod, said cam blade having an inclined cam surface and slideably extending into said cam slot; and means attached to said actuator element for controlling said slideable movement of said actuator element.
 2. A clamping device for holding sheet material comprising: a support member having an upper portion and a lower portion; a pair of clamp jaws pivotally attached to said lower portion of said support member and having a pair of interior flanges; an actuator element slideably mounted within said support member; means located between said actuator element and said pair of clamp jaws for pivoting said pair of clamp jaws in response to the slideable movement of said actuator element, said means for pivoting said pair of clamp jaws comprises a push rod, having its lower end in contact with said actuator element, a cam member attached to said support member and located between said lower end and said upper end of said push rod, and a cam surface on said actuator element in slideable contact with said cam member for moving said push rod to pivot said pair of clamp jaws; and means attached to said actuator element for controlling said slideable movement of said actuator element.
 3. A clamping device for holding sheet material comprising: a support member having An upper portion and a lower portion; a pair of clamp jaws pivotally attached to said lower portion of said support member; an actuator element slideably mounted within said support member; means located between said actuator element and said pair of clamp jaws for pivoting said pair of clamp jaws in response to the slideable movement of said actuator element; and means attached to said actuator element for controlling said slideable movement of said actuator element, said controlling means comprising a control knob rotatably mounted on the end of said support member, a threaded shaft extending from said knob through said support member, and a connecting bracket threadably mounted on said shaft and attached to said actuator element, so that, as said knob is rotated, said actuator element will move longitudinally.
 4. A clamping device for holding sheet material comprising an elongated support member having an upper portion and a lower portion; a pair of clamp jaws pivotally mounted to said lower portion of said support member; an actuator element slideably mounted along the longitudinal axis of said support member; cam means is responsive contact with said actuator element for pivotally moving said pair of clamp jaws; a lever, having one end pivotally attached to said support member; a linkage member having one end pivotally attached to said lever and the other end pivotally attached to said actuator element; and means located between said linkage member and said actuator element for slideably moving said actuator element in response to the movement of said lever.
 5. A clamping device for holding sheet material comprising: a support member having an upper portion and a lower portion; a pair of clamp jaws pivotally attached to said lower portion of said support member; an actuator element slideably mounted within said support member; means located between said actuator element and said pair of clamp jaws for pivoting said pair of clamp jaws in response to the slideable movement of said actuator element; and means attached to said actuator element for controlling said slideable movement of said actuator element, said controlling means comprises a lever having one end pivotally attached to said support member, a linkage member having one end pivotally attached to said lever and the other end pivotally attached to said actuator element, and means located between said linkage member and said actuator element for slideably moving said actuator element in response to the movement of said lever, said means for slideably moving said actuator element comprises a slide shaft attached to said actuator element, a slide ram mounted on said slide shaft, an adjustable restraining ring mounted on said slide shaft, and a spring mounted on said slide shaft between said slide ram and said adjustable ring, so that as said lever is rotated in a downward direction, said linkage member will cause said slide ram to compress said spring against said restraining ring, causing said actuator element to move longitudinally.
 6. A clamping device comprising: a support member; a first holding member, having a pivot leg and a gripping leg, the lower end of said pivot leg being connected at an angle to the upper end of said gripping leg, forming a rigid junction; a second holding member, having a pivot leg and a gripping leg, the lower end of said pivot leg being connected at an angle to the upper end of said gripping leg, forming a rigid junction, said rigid junction of said first holding member and said rigid junction of said second holding member being pivotally attached to said support member; and means located in said support member for urging the movement of said pivot legs of said holding members, so that the lower ends of said gripping legs will move toward each other, said means for urging the movement of said pivot legs of said holding members comprises a slide element slideably mountEd for longitudinal movement within said support member, above said holding members, said slide element having a cam slot, a cam rod located under said pivot legs of said holding members, said cam rod having a cam blade with an inclined cam surface extending into said cam slot, so that said longitudinal movement of said slide element causes vertical movement of said cam rod to pivot said holding members, and means for controlling said longitudinal movement of said slide element.
 7. A clamping device as defined in claim 6, wherein said means for controlling said longitudinal movement of said slide element comprises: a control knob rotatably mounted on said support member; a threaded shaft extending from said knob through said support member; and a connecting bracket threadably mounted on said shaft and attached to said slide element, so that as said knob is rotated, said slide element will move longitudinally.
 8. A clamping device as defined in claim 6, wherein said means for controlling said longitudinally movement of said slide element comprises: a lever, having one end pivotally attached to said support member; a linkage member having one end pivotally attached to said lever and the other end pivotally attached to said slide element; and means located between said linkage member and said slide element for slideably moving said slide element in response to the movement of said lever.
 9. A clamping device comprising: a support member; a first holding member, having a pivot leg and a gripping leg, the lower end of said pivot leg being connected at an angle to the upper end of said gripping leg, forming a rigid junction; a second holding member, having a pivot leg and a gripping leg, the lower end of said pivot leg being connected at an angle to the upper end of said gripping leg, forming a rigid junction, said rigid junction of said first holding member and said rigid junction of said second holding member being pivotally attached to said support member; and means located in said support member for urging the movement of said pivot legs of said holding members, so that the lower ends of said gripping legs will move toward each other, said means for urging the movement of said pivot leg of said holding members comprises, a push rod, having a lower end and an upper end, said lower end being attached to said pivot legs of said first and second holding members, such that vertical movement of said push rod pivots said holding members, a cam member attached to said support member and located between said lower end and said upper end of said push rod, a slide element slideably mounted within said support member, a cam surface on said slide element, said cam surface being in slideable contact with said cam member, so that the longitudinal movement of said slide element will cause the vertical movement of said push rod, and means for controlling said longitudinal movement of said slide element.
 10. A clamp device comprising: a channel member, having an upper section and a lower section; an actuator element slideably mounted longitudinally within said channel member and having a cam slot; means attached to said actuator element for controlling the movement of said actuator element; a pair of clamp members, having a bearing leg and a gripping leg and being pivotally attached to said channel member at the rigid angular junction of said bearing leg and said gripping leg; a cam rod located between said bearing legs of said pair of clamp members, said cam rod being wider than the distance between the upper ends of said bearing legs; means for biasing said gripping legs in the open position; and a cam blade attached to the upper side of said cam rod and extending slideably into said cam slot of said actuator element, said cam blade having an inclined cam surface, so that, as said actuator element is longitudinally moved, said cam rod will move vertically, causing said bearing legs to move Down or up, resulting in said gripping legs opening or closing.
 11. A clamp device as defined in claim 10, wherein said means for controlling the movement of said actuator element comprises: a control knob rotatably mounted on said channel member; a threaded shaft extending from said knob and through said channel member; and a connecting bracket threadably mounted on said shaft and attached to said actuator element, so that, as said knob is rotated, said actuator element will move longitudinally.
 12. A clamp device as defined in claim 10, wherein said means for controlling the movement of said actuator element comprises: a lever, having one end pivotally attached to said channel member; a linkage member, having one end pivotally attached to said lever and the other end pivotally attached to said actuator element; and means located between said linkage member and said actuator element for slideably moving said actuator element in response to the movement of said lever.
 13. A clamp device as defined in claim 10, wherein said means for biasing said gripping legs in the open position comprises a spring biased against the interior sides of said gripping legs of said pair of clamp members.
 14. A clamping device comprising: a channel member; a first leg extending downward from said channel member; a second leg extending downward from said channel member, forming an open channel with said first leg; a pair of support flanges respectively attached to the interior surfaces of said first and second legs, said support flanges in alignment with each other, forming a longitudinal slot; a pair of gripping jaws pivotally attached to respective lower ends of said first and second legs; and camming means located on the upper surface of said support flanges, movement of said gripping jaws responsive to said camming means.
 15. A clamping device comprising: a channel member; a first leg extending downward from said channel member; a second leg extending downward from said channel member, forming an open channel with said first leg; a pair of support flanges respectively attached to the interior surfaces of said first and second legs, said support flanges in alignment with each other, forming a longitudinal slot; a pair of gripping jaws pivotally attached to respective lower ends of said first and second legs; and means located on the upper surface of said support flanges and attached to said gripping jaws for pivoting said gripping jaws, said means for pivoting said gripping jaws comprises: a push rod, having a top flange, said push rod connected to said gripping jaws; an elongated bottom spring member located on said upper surface of said support flanges and below said top flange of said push rod, said bottom spring member having a series of hills and valleys; an elongated top spring member located between said bottom spring member and said top flange of said push rod, said top spring member having a series of hills and valleys, so that, as said top spring member is longitudinally slid over said bottom spring member, said push rod will be in the upper position when said valleys of said top spring member contact said hills of said bottom spring members and said push rod will be in the lower position when said valleys of said top spring member contact said valleys of said bottom spring member; and means for controlling said longitudinal movement of said elongated top spring member.
 16. A clamp apparatus comprising: a support member, having an upper portion and a lower portion; a pair of pivoting gripping arms attached to said lower portion of said support member, said gripping arms having a gripping end and an actuating end; a push rod mounted within said support member and attached to said actuating ends of said pair of gripping arms; and means located within said support member for vertically moving said push rod, causing said pIvoting movement of said gripping arms, said means for vertically moving said push rod comprises: a cam mounted within said support member; an actuator element slideably mounted longitudinally within said support member between said push rod and said pair of gripping arms, said actuator element having a cam surface, so that as said actuator element is longitudinally moved, the contact of said cam of said support member and said cam surface of said actuator element will cause said push rod to move vertically; and means attached to the end of said actuator element for controlling said longitudinal movement of said actuator element. 